Roadster Shop Fast Track IRS

[Roadster Shop]

Originally Posted by fbm37

wow that is truly amazing and looks incredible ....I guess we will have to have one of those next...

Its not too late to put one under that Mustang!

Originally Posted by Bryce

Very nice looking stuff. IS that a 9" ford center section?

Yes, it is an aluminum 9" Ford center, C6 Vette Spindles, fabricated control arms.

Originally Posted by Ron in SoCal

Man that is slick! Any info on hp ratings?

We are going to offer 3 configurations based on the axles and CV rating. 600 HP, 1,000 HP, and 1,400 HP. Ford 9" center sections can be built accordingly. The stub axles are 31 spline or 35 spline. There are not a lot of options currently for the 35 spline in a street application, but several companies are developing a tru-trac type posi for a 35 spline axle that should be out by the end of summer.

Originally Posted by 67ragtp

Most impressive! Have you guys done some testing, Test car? WOW! Beautiful work, I got to have one for my 65 gto project.

Rich

We have not done any real world testing just yet, but have spent a solid 6 months of time on the computer going through suspension analyzing software. Two of the first production units are currently going under test cars that will be on the road very shortly. We are installing a chassis under a 66 Chevelle for a customer, and building a test car for ourselves. We currently have the IRS in both 64-67 and 68-72 Chevelle (and GTO) chassis as well as 1st and 2nd gen Camaro Chassis, and Challenger/Cuda Chassis. Mustang chassis are next on our drawing board to incorporate the IRS into.

[67ragtp]

What are thoughts on exhaust/tail pipe routing? Dumps? Is there enough room under the center section?

Thanks Rich

[Roadster Shop]

Originally Posted by 67ragtp

What are thoughts on exhaust/tail pipe routing? Dumps? Is there enough room under the center section?

Thanks Rich

Rich,
The crossmember has two recesses in it to allow for 3" exhaust to pass above the axle. There are holes there for an exhaust mount that we are going to offer as an option. We are going to be starting on the exhaust for chris's 66 chevelle in the project section. I'll get a few pics posted as we get there.

[Autokraft]

What is the track width on the rear? Looks awesome

[96z28ss]

This is a really cool way to get IRS in side a muscle car.
Tim Bruning has done a similar set up before at SAR. SAR used more GM Facotry components. There hasn't been any true hard testing of the system. Show car type stuff.
Lets get some real world testing!!

[Roadster Shop]

Originally Posted by 96z28ss

This is a really cool way to get IRS in side a muscle car.
Tim Bruning has done a similar set up before at SAR. SAR used more GM Facotry components. There hasn't been any true hard testing of the system. Show car type stuff.
Lets get some real world testing!!

We are working to have Chris's 66 out for the Motor State Event with the IRS and we will have a 2nd gen of our own shortly behind that.

SAR definitely does some top notch stuff. We looked at the stock C6 components and saw a lot of room for improvement. By building our own conrtol arms and cradle system we were to make several improvements over a stock C6 IRS.

We have increased camber gains in roll compared to stock C6. There is 1 degree of negative camber gain through 1" of compression. This makes sure your tires never gain positive camber (like a stock C6) during cornering, losing traction/grip.

We were able to closely match camber gains to that of our front suspension which will yield a much more balanced and predictable car

Upper and lower control arm mounting points are pitched to give your vehicle 55% anti-squat, NO OTHER IRS OFFERS THIS, (Anti-squat will make your tires plant harder to the ground to help with acceleration and traction out of corners and from a launch)

We were also able to stand up the coilovers drastically over what is possible on a stock C6 arm giving more desirable a motion ratio.

Our upper control arms are also easily adjustable so caster/camber can be adjusted with shims while at the track.

[Roadster Shop]

Originally Posted by Autokraft

What is the track width on the rear? Looks awesome

Thanks, the track width is 58.75" which will end up at 59" with brakes. We had a lot of discussion about track widths and possibly going narrower to get a deeper lip on the rear wheels, but decided on maintaining the optimal geometry and performance rather than sacrifice that for looks of the rear wheel. We designed it to be considerably narrower than a stock C6 Vette IRS. Depending on the car, you should be in the 6" - 9" back space range on a 12" wheel.

[esenior]

Originally Posted by Roadster Shop

Rich,
The crossmember has two recesses in it to allow for 3" exhaust to pass above the axle. There are holes there for an exhaust mount that we are going to offer as an option. We are going to be starting on the exhaust for chris's 66 chevelle in the project section. I'll get a few pics posted as we get there.

Sorry to revive an old post, but am very interested in going with the Fast Track w/IRS for a 68 Camaro convertible build.

I wanted to know more about the exhaust. I saw in some pics how the exhaust runs through the top of the IRS, but how do you run it behind the axle? The website mentions that a stock tank fits, but in some of the pictures in the build thread, it looks like you have to run a custom tank. Can you let me know what the options are? Thanks!

[Roadster Shop]

The build thread that you referenced is not a great example to look at in regards to your questions. That car had a complete custom chassis built for it with a lot of unique components and ideas.

When running the IRS on a 1st gen camaro, you can no longer run the stock tank. (you can run the stock tank with the solid axle 9" rear suspension) A custom tank would have to be built. Rick's Tanks or Rock Valley can both provide you with that end of the build for $1,000 - $1,500 depending on your motor's fuel pump requirements.

Here are a few good shots of the exhaust and fuel tank on a 66 Chevelle with the IRS. It is a different car, but similar idea on the tank and exhaust. The customer wanted the exhaust run on the outside of the frame rails on this car. You could also run the exhaust inside the frame rails and make a narrower tank.

[esenior]

Thanks for the update...glad to hear a tank is readily available (was planning on going with a Rick's tank already).

Still looking at all of my options...don't plan to start the project until next summer (car just arrived yesterday). Already have the wife on board with the LSA/4L85E. Hoping I can convince her that the full chassis with IRS is the way to go

P.S. Love your last picture!

Here's our next project....